A Docker Captain's Blog

Docker | Kubernetes | Cloud

Docker 17.06.0-ce-RC5 got announced 5 days back and is available for testing. It brings numerous new features & enablements under this new upcoming release. Few of my favourites includes support for Secrets on Windows, allows specifying a secret location within the container, adds --format option to docker system df command, adds support for placement preference to docker stack deploy, adds monitored resource type metadata for GCP logging driver and adding build & engine info prometheus metrics to list a few. But one of the notable and most awaited feature include support of swarm-mode services with node-local networks such as macvlan, ipvlan, bridge and host.

Under the new upcoming 17.06 release, Docker provides support for local scope networks in Swarm. This includes any local scope network driver. Some examples of these are bridge, host, and macvlan though any local scope network driver, built-in or plug-in, will work with Swarm. Previously only swarm scope networks like overlay were supported. This is a great news for all Docker Networking enthusiasts.

A Brief Intro to MacVLAN:

In case you’re new , the MACVLAN driver provides direct access between containers and the physical network. It also allows containers to receive routable IP addresses that are on the subnet of the physical network.

MACVLAN offers a number of unique features and capabilities. It has positive performance implications by virtue of having a very simple and lightweight architecture. It’s use cases includes very low latency applications and networking design that requires containers be on the same subnet as and using IPs as the external host network.The macvlan driver uses the concept of a parent interface. This interface can be a physical interface such as eth0, a sub-interface for 802.1q VLAN tagging like eth0.10 (.10representing VLAN 10), or even a bonded host adaptor which bundles two Ethernet interfaces into a single logical interface.

To test-drive MacVLAN under Swarm Mode, I will leverage the existing 3 node Swarm Mode clusters on my VMware ESXi system. I have tested it on bare metal system and VirtualBox and it works equally great.

[Updated: 9/27/2017 – I have added docker-stack.yml at the end of this guide to show you how to build services out of docker-compose.yml file. DO NOT FORGET TO CHECK IT OUT]

Installing Docker 17.06 on all the Nodes:

curl -fsSL https://test.docker.com > install-docker.sh

sh install-docker.sh

Verifying the latest Docker version:

Setting up 2 Node Swarm Mode Cluster:

Attention VirtualBox Users:– In case you are using VirtualBox, the MACVLAN driver requires the network and interfaces to be in promiscuous mode.

A local network config is created on each host. The config holds host-specific information, such as the subnet allocated for this host’s containers. --ip-range is used to specify a pool of IP addresses that is a subset of IPs from the subnet. This is one method of IPAM to guarantee unique IP allocations.